This invention relates in general to reducing the static magnetic field signature of marine vessels by use of hull mounted loop coils through which electrical currents are conducted for magnetic degaussing purposes.
The use of hull mounted degaussing coils in an attempt to cancel or reduce static magnetic field signatures of naval vessels to minimize mine detection for example, is already well known in the art as referred to in a related copending application, Ser. No. 08/115,075, filed Sep. 1, 1993 and officially allowed on Jul. 19, 1995. Pursuant to such magnetic degaussing systems, orthogonal sets of degaussing coil loops are respectively aligned in perpendicular planes to reduce magnetization field components, involving what are referred to in the prior art as A-coil, L-coil and M-coil arrangements. Such systems sometimes feature automatic controls for varying current conducted through the degaussing coils in accordance with parameters which affect the vessel's magnetic field signature, such as geometric heading, roll, pitch and yaw. For example, current control for the M-coil loop in a horizontal degaussing plane to compensate for vertical components of a ship's magnetic field is disclosed in each of U.S. Pat. Nos. 2,519,395 and 2,718,205 to Perlow and Febs et al., respectively. The Perlow patent also discloses variation of current in a degaussing coil loop positioned in alignment with a longitudinally extending vertical plane to neutralize transverse magnetization of a vessel in a horizontal plane as a trigometric function of the vessel heading.
It is therefore an important object of the present invention to provide a loop coil degaussing system which is capable of reducing the magnetic field signature of a vessel to levels lower than that possible with existing conventional systems.
A further object of the invention in accordance with the foregoing object is to achieve magnetic field signature reduction with a degaussing coil loop arrangement of reduced cost.